Use released delayed_job instead of master version

Ref: https://github.com/collectiveidea/delayed_job/blob/master/CHANGELOG.md#414---2017-12-29

Gemfile

@@ -61,7 +61,7 @@ group :job do
   gem "resque-scheduler", require: false
   gem "sidekiq", require: false
   gem "sucker_punch", require: false
-  gem "delayed_job", require: false, github: "collectiveidea/delayed_job"
+  gem "delayed_job", require: false
   gem "queue_classic", github: "QueueClassic/queue_classic", branch: "master", require: false, platforms: :ruby
   gem "sneakers", require: false
   gem "que", require: false

Gemfile.lock

@@ -6,13 +6,6 @@ GIT
     queue_classic (3.2.0.RC1)
       pg (>= 0.17, < 0.20)
 
-GIT
-  remote: https://github.com/collectiveidea/delayed_job.git
-  revision: 6cf9b0b2c256d20148172d074ca60e13d6439903
-  specs:
-    delayed_job (4.1.3)
-      activesupport (>= 3.0, < 5.2)
-
 GIT
   remote: https://github.com/matthewd/rb-inotify.git
   revision: 856730aad4b285969e8dd621e44808a7c5af4242
@@ -208,6 +201,8 @@ GEM
     dante (0.2.0)
     declarative (0.0.10)
     declarative-option (0.1.0)
+    delayed_job (4.1.4)
+      activesupport (>= 3.0, < 5.2)
     delayed_job_active_record (4.1.2)
       activerecord (>= 3.0, < 5.2)
       delayed_job (>= 3.0, < 5)
@@ -518,7 +513,7 @@ DEPENDENCIES
   chromedriver-helper
   coffee-rails
   dalli (>= 2.2.1)
-  delayed_job!
+  delayed_job
   delayed_job_active_record
   google-cloud-storage (~> 1.8)
   hiredis